From 7619625403ef9de5dca0cfce8e81d9f54a3b722d Mon Sep 17 00:00:00 2001
From: nedko <nedko@internedko.net>
Date: Tue, 30 Jun 2026 17:00:16 +0300
Subject: [PATCH] Fixed time alignment

---
 TRMNL.cpp | 41 +++++++++++++++++++++++++----------------
 1 file changed, 25 insertions(+), 16 deletions(-)

diff --git a/TRMNL.cpp b/TRMNL.cpp
index 52c8f9b..697a77b 100644
--- a/TRMNL.cpp
+++ b/TRMNL.cpp
@@ -1,11 +1,14 @@
 #include "TRMNL.h"
 #include "helpers.h"
 
+#include <set>
+
 #include <time.h>
 
 using std::list;
 using std::map;
 using std::optional;
+using std::set;
 using std::string;
 
 using nlohmann::json;
@@ -78,31 +81,37 @@ int TRMNL::get_next_refresh(int min_time, int offset) const
 	struct tm* now = localtime(&curr);
 
 	int tmp_refresh = m_refresh_rate;
-	bool align_minutes = false;
-	bool align_hours = false;
+	set<int> allowed_minutes = {0, 1, 2, 3, 4, 5, 6, 10, 12, 15, 20, 30};
+	set<int> allowed_hours = {1, 2, 3, 4, 6, 8, 12, 24};
 
+	// Check whether refresh rate is minutes aligned
 	if (0 == m_refresh_rate % 60)
 	{
-		align_minutes = true;
 		tmp_refresh /= 60;
+		now->tm_sec = 0;
 
+		// Check whether refresh rate is hours aligned
 		if (0 == tmp_refresh % 60)
 		{
-			align_hours = true;
 			tmp_refresh /= 60;
+			now->tm_min = 0;
+
+			// Hours within the day
+			if (0 != allowed_hours.count(tmp_refresh))
+			{
+				now->tm_hour -= now->tm_hour % tmp_refresh;
+			}
+			now->tm_hour += tmp_refresh;
+		}
+		else
+		{
+			// Minutes within the hour
+			if (0 != allowed_minutes.count(tmp_refresh))
+			{
+				now->tm_min -= now->tm_min % tmp_refresh;
+			}
+			now->tm_min += tmp_refresh;
 		}
-	}
-
-	if (align_minutes)
-	{
-		now->tm_sec = 0;
-		now->tm_min += 1;
-	}
-
-	if (align_hours)
-	{
-		now->tm_min = 0;
-		now->tm_hour += 1;
 	}
 
 	time_t next = mktime(now);